Differences in particulate matter retention and leaf microstructures of 10 plants in different urban environments in Lanzhou City.

Particulate matter (PM) is a major primary environmental air pollutant and poses a threat to human health. Differences in the environment and leaf microstructures of plants will result in varying abilities to retain PM, but the effects of changes in these factors on PM retention are not yet well understood. This study selected 10 plant species in four urban areas (sports field, park, residential green space, and greenway) as the study objects. The amount of retained PM by the different species was measured, and the leaf microstructures were observed. It was found that the environment significantly affected both PM retention and leaf microstructure. The ranking of PM retention in the 10 species in four areas was greenway > residential green space > park > sports field. The ranking of average stomatal width and length was park > sports field > residential green space > greenway, while that of average stomatal density was greenway > residential green space > park > sports field. Different environments affected the length and density of trichomes in the leaves. These changes represented the adaptation of plant species to the growth environment. The stomata and grooves of the leaf surface significantly affected the ability of plants to retain PM. The amount of PM retained by different species varied. In all four urban areas, Prunus × cistena N. E. Hansen ex Koehne (purple leaf sand cherry), Prunus cerasifera Ehrhart f. atropurpurea (Jacq.) Rehd. (cherry plum), Buxus sinica var. parvifolia M. Cheng (common boxwood), and Ligustrum × vicaryi Rehder (golden privet) showed strong PM retention. The results of this study will provide information for planners and urban managers for the selection of plant species.

Gmelina arborea- an indigenous timber species of India with high medicinal value: A review on its pharmacology, pharmacognosy and phytochemistry.

ETHNOPHARMACOLOGICAL SIGNIFICANCE: Gmelina arborea Roxb.ex Smith, a fast-growing deciduous tree belongs to the family Lamiaceae, and is an important plantation species in many tropical areas around the world. The species is naturally distributed in semi-deciduous forests in tropical/subtropical regions of South East Asia. The tree is also an important medicinal plant in the Indian Systems of Medicine. The whole plant is used in medicine. It is astringent, bitter, digestive, cardiotonic, diuretic, laxative and pulmonary and nervine tonic. It improves digestion, memory, helps overcome giddiness and is useful in burning sensation, fever, thirst, emaciation, heart diseases, nervous disorders and piles. The roots are acrid, bitter-sweet in taste, stomachic, tonic, laxative, galactagogue and antihelmintic. The flowers are sweet, refrigerant, bitter, astringent and acrid, and are used in treating leprosy and skin diseases. The fruits are acrid, sour, sweet, refrigerant, bitter, astringent, aphrodisiac, trichogenous, alterant and tonic. Fruits are edible and also used for promoting hair growth and in treating anaemia, leprosy, ulcers, constipation, leucorrhoea and colitis. The leaves are a good fodder also. The major bioactive compounds extracted from different parts of G. arborea are arboreal, verbascoside, tyrosol, iridoids, phenylpropanoid glycoside, premnazole, martynoside, iridoid glycosides, balanophonin, gmelinol, isoarboreol apigenin, umbelliferone etc. AIM OF THE REVIEW: This review provides an insight into the medicinal aspects of G. arborea. It provides the latest information on phytochemistry, pharmacological activities and traditional uses of G.arborea. MATERIALS AND METHODS: Information on G. arborea was gathered from various sources like textbooks, literature, databases such as PubMed, Science Direct, Wiley, Springer, Taylor and Francis, Scopus, Inflibnet, Sci-Finder and Google Scholar. RESULTS: Sixty-nine phytochemicals which include lignans, acylated iridoid glycosides, acylated rhamnopyranoses, flavonoids, flavones, flavone glycosides have been isolated. Many of them have been characterized for their pharmacological activity. Several researchers have identified bioactive phytochemicals like luteolin, iridoid alkaloids from the leaves, hentriacontanol and lignans such as arboreol, isoarboreol, arborone, gmelanone, gummadiol from the heartwood, flavon glycosides in roots. The extracts are reported to have wound-healing and antidiarrheal properties. Various studies demonstrated that G.arborea and its constituents possess several pharmacological activities like anti-oxidant, anti-diabetic, anti-inflammatory, antiulcer, analgesic, anti-nociceptive, anticancer and wound healing activities. CONCLUSION: G. arborea is a valuable medicinal plant used traditionally in the Indian Systems of Medicine (ISM - Ayurveda and Unani) to treat a wide variety of ailments. These phytochemicals are highly bioactive and exhibit various pharmacological activities. However, pharmacological activities of many compounds which have been identified, are yet to be understood.